package org.apache.solr.search.function.distance;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.spell.StringDistance;
import org.apache.solr.search.function.DocValues;
import org.apache.solr.search.function.ValueSource;

import java.io.IOException;
import java.util.Map;

/**
 *
 *
 **/
public class StringDistanceFunction extends ValueSource {
	protected ValueSource str1, str2;
	protected StringDistance dist;

	/**
	 * @param str1
	 * @param str2
	 * @param measure
	 */
	public StringDistanceFunction(ValueSource str1, ValueSource str2,
			StringDistance measure) {
		this.str1 = str1;
		this.str2 = str2;
		dist = measure;

	}

	@Override
	public DocValues getValues(Map context, IndexReader reader)
			throws IOException {
		final DocValues str1DV = str1.getValues(context, reader);
		final DocValues str2DV = str2.getValues(context, reader);
		return new DocValues() {

			@Override
			public float floatVal(int doc) {
				return dist.getDistance(str1DV.strVal(doc), str2DV.strVal(doc));
			}

			@Override
			public int intVal(int doc) {
				return (int) doubleVal(doc);
			}

			@Override
			public long longVal(int doc) {
				return (long) doubleVal(doc);
			}

			@Override
			public double doubleVal(int doc) {
				return (double) floatVal(doc);
			}

			@Override
			public String toString(int doc) {
				StringBuilder sb = new StringBuilder();
				sb.append("strdist").append('(');
				sb.append(str1DV.toString(doc)).append(',')
						.append(str2DV.toString(doc)).append(", dist=")
						.append(dist.getClass().getName());
				sb.append(')');
				return sb.toString();
			}
		};
	}

	@Override
	public String description() {
		StringBuilder sb = new StringBuilder();
		sb.append("strdist").append('(');
		sb.append(str1).append(',').append(str2).append(", dist=")
				.append(dist.getClass().getName());
		sb.append(')');
		return sb.toString();
	}

	@Override
	public boolean equals(Object o) {
		if (this == o)
			return true;
		if (!(o instanceof StringDistanceFunction))
			return false;

		StringDistanceFunction that = (StringDistanceFunction) o;

		if (!dist.equals(that.dist))
			return false;
		if (!str1.equals(that.str1))
			return false;
		if (!str2.equals(that.str2))
			return false;

		return true;
	}

	@Override
	public int hashCode() {
		int result = str1.hashCode();
		result = 31 * result + str2.hashCode();
		result = 31 * result + dist.hashCode();
		return result;
	}
}
